Image-generating, endoluminal instruments can be used for recording two-dimensional images of the interior of a hollow channel, in particular of a vessel or a hollow organ. Image-generating methods such as intravascular ultrasound (IVUS), optical coherence tomography (OCT) or fluorescence imaging are used in this area. The images are recorded here during the continuous or stepwise monitored movement of the instrument in the hollow channel. Thus, image-generating intravascular catheters for example can be used to produce two-dimensional cross-sectional images from the interior of vessels, from the vascular system of the heart for example. In this regard FIG. 1 shows by way of example a cross-section through a vascular system 3, with the image-generating catheter 1 introduced into one of the vessels 2 being recognizable in the figure. Said catheter 1 is advanced or retracted in the vessel either mechanically or manually by means of a movement control device 4. The pull direction of the catheter 1 is indicated by the arrow. Two-dimensional cross-sectional images of the vessel are recorded at regular intervals during the continuous, monitored movement of the catheter 1 in the vessel 2. The 2D cross-sectional images 5 obtained at different positions in the vessel 2 during the movement of the catheter 1, each of which represents a cross-section transversely to the longitudinal axis of the vessel 2, are shown on the right-hand side of FIG. 1. The arrow running along the 2D cross-sectional images 5 represents the direction in which the catheter 1 is pulled during the recording of the image. The 2D cross-sectional images show the vessel wall 7 and the central axis 8 of the vessel within the vessel lumen 6 on which the catheter 1 is guided.
DE 199 19 907 A1 discloses a method of catheter navigation in three-dimensional vascular tree images in which the spatial position of the catheter is detected and inserted into a 3D view of a preoperatively recorded vascular tree. For this purpose a catheter having an integrated position sensor is used by means of which the current spatial position of the catheter tip is detected. By registration of the position sensor with the 3D image data it is possible to display the current spatial position at any given time at the correct position in the 3D view.
The use of an image-generating endoluminal instrument, a catheter or endoscope for example, having a position sensor enables the three-dimensional reconstruction of the anatomy mapped by means of the catheter from the recorded sequence of 2D image data. The position sensing during the image recording also permits the assignment to intraoperative 2D X-ray fluoroscopy images, with the aid of which the user has points of reference when guiding the catheter. It is furthermore possible on account of the knowledge of the respective spatial position during the recording of each image to register or fuse the recorded 2D image data in a simplified manner with 3D image data obtained either preoperatively, by means of computer tomography or magnetic resonance tomography for example, or intraoperatively, by means of 3D rotation angiography or 3D ultrasound for example.